Pulmonary Physiology

Front 1

Where is the most resistance in the airways?

Back 1

Medium sized bronchi. Smallest bronchi are not the most resistance because of their parallel orientation

Front 2

What is the function of surfactant? How does it work?

Back 2

Reduces surface tension by disrupting intermolecular forces between liquid molecules.

Increases compliance of the alveolus.

Front 3

What is the main component of surfactant?

Back 3

phospholipids (80%) - main one is DPCC

Front 4

What is neonatal respiratory distress syndrome?

Back 4

Lack of surfactant in premature infants causes atelectasis, difficulty reinflating lungs (decreased compliance), hypoxemia because of decreased V/Q

Front 5

What is the equation that relates pressure, airflow, resistance?

Units of resistance?

Back 5

Q = delta P/R

R = cmH20/L/min

Front 6

Which volumes cannot be measured by spirometry?

Back 6

Anything that involves residual volume: Residual volume, functional residual capacity, total lung capacity

Front 7

Equation to calculate physiologic dead space

Back 7

Vd = Vt x (PACO2 - PECO2)/PACO2

A = alveolar gas
Vt = tidal volume

Front 8

What is inspiratory capacity the sum of?

Back 8

Tidal volume + inspiratory reserve volume

Front 9

What makes up FRC?

Back 9

Functional residual capacity = RV + Expiratory reserve volume

Front 10

What makes up vital capacity

Back 10

Sum of ERV + TV + IRV

Front 11

What is normal FEV1/FVC

Back 11

80%

Front 12

Asthma - obstructive or restrictive? what happens?

Back 12

Asthma is obstructive lung disease. Reduced FEV1, reduced FVC, low FEV1/FVC ratio

Front 13

Fibrosis - obstructive or restrictive? What happens?

Back 13

Restrictive. Reduced compliance. Everything reduced almost same, so FEV1/FVC ratio stays normal or increased.

Front 14

Muscles of inspiration

Back 14

diaphragm (pushes everything down), external intercostals (elevate)

Front 15

Muscles of expiration

Back 15

Expiration is normally passive. Active respiration is abdominal muscles and internal intercostal muscles.

Front 16

Transpulmonary pressure = ?

Back 16

Alveolar pressure - intrapleural pressure

Front 17

What is hysteresis?

Back 17

Inflation follows a different curve than deflation of the lung

Front 18

What happens to compliance in emphysema

Back 18

Lung compliance increased (tendency of lungs to collapse decreased); new, higher FRC comes and chest becomes barrel shaped

Front 19

Fibrosis and compliance?

Back 19

Compliance is decreased, tendency to collapse is increased, so there is a lower FRC

Front 20

At rest, what are the pressures of interpleural cavity and alveoli relative to atm pressure?

Back 20

Alveolar pressure = atm pressure; intrapleural pressure is negative because the lungs want to collapse and the chest wall wants to expand

Front 21

When you are inspiring, what happens to the pressures as the thoracic space increases?

Back 21

lung volume expands, so the pressure in the lungs becomes less than atm pressure, and the pressure gradient allows air to flow into lungs

Front 22

During expiration, what happens to the alveolar and intrapleural pressures?

Back 22

alveolar pressure becomes greater than atm pressure and air flows out of the lungs

Front 23

COPD - obstructive or restrictive? what happens to compliance? FEV1/FVC ratio?

Back 23

obstructive; compliance increases --> barrel chest; FEV1/FVC ratio down

Front 24

What is the P02 in the air? in the alveoli air? in the arterial blood? in the venous blood?

Back 24

Air = 150 mmHg; alveoli = 100mmHg; blood = 100; venous = 40

Front 25

What is the PCO2 in air? in alveoli? in arteries? in veins?

Back 25

Air = 0; alveoli = 40; arteries = 40; veins = 46

Front 26

What is methemoglobin?

Back 26

Fe2+ is normal state of iron in heme moiety of hemoglobin; methemoglobin is iron in Fe3+ state

Front 27

What limits the amount of O2 that can be carried in the blood?

Back 27

O2 saturation of hemoglobin

Front 28

What is the Carboxyhemoglobin?

What is carbaminoHb?

Back 28

carboxy = CO + Hb

carbamino = CO2 + Hb

Front 29

What is the major form in which CO2 is transported to the lungs?

Back 29

HCO3-

H20 + CO2 --> H2CO3 --> HCO3- + H+ (happens in venous blood)

Front 30

What buffers the H+ produced when CO2 breaks down to bicarbonate and H+?

Back 30

deoxyhemoglobin

Front 31

Zone 1 pressures

Back 31

P alveolar > Parterial > P venous

Front 32

Zone 2 pressures

Back 32

P arterial > P alveolar > P venous

Front 33

Zone 3 pressures

Back 33

P arterial > P venous > P alveolar

Front 34

Do lungs vasoconstrict or vasodilate in response to hypoxia?

Back 34

Vasoconstrict; this way poorly ventilated regions will not have too much perfusion either; this happens when PO2 falls to low levels, esp when pH is more acidic (less than 7.4) as happens when pCO2 levels are high.

Front 35

How does V/Q ratio change from apex to base of lung?

Back 35

Apex: High ventilation, low perfusion = high V/Q ratio

Base: Low ventilation, high perfusion = Low V/Q ratio

Front 36

Which part of the brain controls breathing?

Back 36

brain stem

Front 37

Where are central chemoreceptors? What stimuli cause them to increase breathing?

Back 37

Medulla; hyperventilation caused by decreased pH, increased pC02

Front 38

Where are peripheral chemoreceptors? What stimuli cause them to increase breathing?

Back 38

carotid and aortic bodies; decreased p02, increased CO2, decreased pH

Front 39

What is the Hering Breuer reflex?

Back 39

Lung stretch receptors are stimulated by distention of lungs and produce a reflex decrease in breathing frequency

Front 40

Where are irritant receptors located? What stimulates them?

Back 40

Located between airway epithelial cells; stimulated by noxious substances (dust, pollen)

Front 41

Which receptors are activated to stimulate breathing during exercise?

Back 41

joint/muscle receptors activated at beginning of exercise

Front 42

What kind of drug will counter the effects of asthma (bronchoconstriction)?

Back 42

B2 adrenergic agonist - produces relaxation of the bronchioles

Front 43

If there is an embolism that blocks blood flow to the left lung, what is the pO2 going to be of the alveoli?

Back 43

Left lung PAO2 will be the same as the inspired air because there is not going to be any gas exchange between the alveoli and the pulmonary capillary blood if there is no perfusion.

Front 44

Why do pulmonary vascular resistance and blood flow vary along the vertical length of the lung?

Back 44

gravitational effects

Hint 44

barrett

Front 45

How is pulmonary vascular resistance affected by changes in pulmonary intravascular pressure (exercise?)

Back 45

goes down

Hint 45

barrett

Front 46

How is PVR affected by positive pressure ventilation?

Back 46

goes up

Hint 46

barrett

Front 47

How is PVR affected by Nitric Oxide?

Back 47

goes down

Hint 47

barrett

Front 48

Does hypoxia increase or decrease PVR? When is this beneficial? When is this detrimental?

Back 48

Hypoxia increases PVR. Good for fetal circulation; bad for high altitude

Hint 48

barrett

Front 49

What's the mean pulmonary arterial pressure?

Mean Left Atrial Pressure?

Back 49

PA - 15mmHg
LA - 5 mmHg

Hint 49

Barrett

Front 50

From the apex to the base of the lung, which of the pressures remains unchanging: P arterial, alveolar, or venous?

Back 50

alveolar

Hint 50

Barrett

Front 51

At what volume is resistance to pulmonary blood flow the least?

Back 51

Functional residual capacity. It increases as the lung is inflated or deflated.

Hint 51

Barrett

Front 52

When the lung is inflated from FRC, what is the reason for the increase in PVR?

Back 52

Alveolar capillaries are getting compressed (they are embedded in the expanding alveolar walls)

Hint 52

Barrett

Front 53

When the lung is deflated from FRC, what is the reason for the increase in PVR?

Back 53

The extra-alveolar capillaries (veins and arteries) are becoming compressed because the intrapleural pressure becomes positive with forced expiration; also radial traction forces become smaller which mean the vessels aren't held open as well.

Hint 53

Barrett

Front 54

Why do pulmonary vascular resistance and blood flow vary along the vertical length of the lung?

Back 54

gravitational effects

Hint 54

barrett

Front 55

How is pulmonary vascular resistance affected by changes in pulmonary intravascular pressure (exercise?)

Back 55

goes down

Hint 55

barrett

Front 56

How is PVR affected by positive pressure ventilation?

Back 56

goes up

Hint 56

barrett

Front 57

How is PVR affected by Nitric Oxide?

Back 57

goes down

Hint 57

barrett

Front 58

Does hypoxia increase or decrease PVR? When is this beneficial? When is this detrimental?

Back 58

Hypoxia increases PVR. Good for fetal circulation; bad for high altitude

Hint 58

barrett

Front 59

Does extra-alveolar PVR go up when lungs go toward TLC or toward RV?

Back 59

RV - Extra-alveolar PVR goes up when the lungs are deflated from FRC.

Hint 59

Barrett

Front 60

Does alveolar PVR go up when lungs go toward TLC or toward RV?

Back 60

TLC - alveolar PVR goes up when the lungs are inflated from FRC

Hint 60

Barrett

Front 61

When is vasoconstriction of lungs in response to hypoxia good? When is it bad?

Back 61

Good in fetal circulation, when blood needs to be shunted away from the lungs. Bad in high altitude, when even well ventilated regions of the lung are hypoxic

Hint 61

barrett

Front 62

In hypoxia, which side of the heart has increased work when PVR increases?

Back 62

Right heart (Right heart pumps blood into pulmonary system, and it's working against a higher resistance to get the blood out)

Hint 62

Barrett

Front 63

What is the difference between interstitial and alveolar edema?

Back 63

Interstitial = thickening of wall parenchyma

Alveolar = fluid accumulation in alveoli

Result of any pulmonary edema = impaired gas transfer

Hint 63

Barrett

Front 64

Factors that lead to pulmonary edema (5)

Back 64

1. Permeability - infections, toxins that destroy the integrity of the capillary endothelium
2. Capillary hydrostatic pressure increases --> fluid goes out of capillary
3. Interstitial hydrostatic pressure decrease --> fluid goes out of capillary
4. Plasma osmotic pressure decrease --> fluid goes out with it
5. Interstitial oncotic pressure increase --> fluid goes out to balance it
6. lymphatic insufficiency

Hint 64

barrett

Front 65

What circulation is sensitive to acetylcholine and tachykinins?

Back 65

tracheobronchial circulation - this is the reason that there is increased permeability of the tracheobronchial blood flow during asthma

Hint 65

barrett

Front 66

What is the functional importance of pulmonary arteries and pulmonary veins running separately?

Back 66

prevents gas exchange/diffusion between arteries and veins; arteries run next to airways and veins run seperate

Front 67

Causes of pulmonary edema (from lecture notes)

Back 67

1. elevated intravascular pressure (ex. left heart failure)
2. Blocked lymphatic drainage
3. Absence of surfactant (only in pulm. circulation)
4. Increased capillary permeability (ex. infection)
5. Loss of plasma proteins

Front 68

What is Fick's Law

Back 68

Vgas = (A/T)D(pA - pB)

V = net rate of gas movement

Front 69

What is the partial pressure of O2 and CO2 in mixed venous blood?

Back 69

O2 = 40
CO2 = 46

Front 70

What is the partial pressure of O2 and CO2 in mixed alveolar air?

Back 70

O2 = 100
CO2 = 40

Front 71

Why does CO2 diffuse at the same rate as O2, even though the pressure gradient is small? (CO2 =6 blood to air and O2=60 air to blood)

Back 71

CO2 is about 20 times more soluble in blood than O2, and thus has a larger diffusion coefficient than O2.

Front 72

What is diffusion equilibrium?

Back 72

pA = pB

Front 73

Why doesn't diffusion normally limit the rates of O2 uptake and CO2 elimination in the lungs?

Back 73

It takes about 1/4 second to reach diffusion equilibrium between the alveoli and the blood, and the exposure in each cardiac cycle is 3/4 seconds.

Front 74

During exercise, is the rate of O2 uptake or CO2 elimination diffusion limited?

Back 74

Neither is diffusion limited for a normal person because even though cardiac output can increase and shorten the time each RBC is exposed to alveolar air, it is still 1/4 second. In trained athletes, it is possible to get diffusion limitation/hypoxia.

Front 75

What are three circumstances in which gas exchange can become diffusion limited?

Back 75

1. trained athlete doing heavy exercise (CO becomes too high and RBCs don't get enough exposure to alveolar air because they are moving so fast.
2. diffusion barrier becomes thicker (pulmonary edema). O2 affected more than CO2.
3. High altitude - smaller O2 gradient driving transfer from alveoli to blood.

Front 76

Is O2 uptake perfusion limited or ventilation limited?

Back 76

Perfusion. O2 uptake can be increased more by increasing rate of pulm. perfusion than by increasing rate of ventilation.

Front 77

Which term in Fick's Law can you use CO to measure?

Back 77

A/T (diffusing capacity of alveolar surface)

pCO in blood is very low so it's transfer is diffusion limited

Front 78

What does it mean when the O2 binding curve of Hb is shifted to the right? What factors can cause this to happen?

Back 78

decreased O2 affinity, increased P50 (pO2 at which 50% Hb saturation). Caused by increased CO2, decrease pH, DPG, elevated temp

Front 79

Equation for O2 capacity

Back 79

1.34 mlO2/gm Hb x Hb concentration = 20.1 mlO2/100gm blood

Normal Hb saturation is 15gm/100ml blood

Front 80

Equation for O2 content

Back 80

O2 capacity (1.34 x Hb conc) + dissolved O2 (O.003 x pO2)

Front 81

3 forms of CO2 carried in blood?

Back 81

dissolved CO2, carbaminoHb, HCO3-

HCO3- is predominant form in arterial and venous blood

Front 82

Which acids are secreted by lungs and kidney (fixed or volatile)

Back 82

Kidney - fixed
Lungs - volatile (ex. H2CO3)

Front 83

What are the roles of the lungs and kidneys in maintaining the plasma pH at 7.4?

Back 83

lungs maintain pCO2 by adjusting rate of alveolar ventilation; kidneys maintain HCO3-

Front 84

What happens in respiratory acidosis?

Back 84

Rise in pCO2 of plasma, usually resulting from impaired gas exchange in lungs (asthma, pneumonia, emphysema, hypoventilation)

Front 85

What happens in respiratory alkalosis?

Back 85

Lowering of pCO2 from an increase in alveolar ventilation not matched by a proportionate increase in CO2 production (from hyperventilation in high altitude, childbirth, etc)

Front 86

In chronic acid-base disturbances (respiratory acidosis or respiratory alkalosis) how does HH equation adjust to compensate?

Back 86

The kidney either lowers plasma HCO3- (alkalosis) or elevates plasma HCO3 (acidosis) to compensate

Front 87

In a respiratory acidosis with elevated pCO2 and HCO3-, which is the primary problem?

Back 87

elevated pCO2. elevated HCO3- is the compensation by the kidney to keep the pH as close to 7.4 as possible.

Front 88

How does the diffusion rate of CO2 affect the diffusion rate of O2?

Back 88

It doesn't; each gas diffuses independently of other gasses.

Front 89

If VCO2 (rate of CO2 production) remains constant, what relationship remains reciprocal (use alveolar ventilation equation)

Back 89

Alveolar ventilation and arterial/alveolar pCO2 will be inversely proportional

Front 90

Why do we use Carbon Monoxide to measure A/T in Fick's Law and not pO2 or pCO2?

Back 90

pO2 and pCO2 change along the length of the alveolar capillary; CO partial pressure changes very little along the length of the alveolar capillary

Front 91

Is the relationship between pO2 and O2 saturation of Hb linear or nonlinear?

Back 91

nonlinear

Front 92

What is the Bohr effect?

Back 92

Acid pH reduces O2 binding to Hb more in the tissues than in the lungs

Front 93

What is the difference between acute and chronic respiratory acidosis?

Back 93

acute = no renal compensation
chronic = renal compensation complete (takes about a week)

Respiratory alkalosis is compensated by renal reduction of HCO3 within 2 days

Front 94

What is the relationship between V/Q and pO2 and V/Q and pCO2?

Back 94

As V/Q decreases, alveolar pO2 goes down and pCO2 goes up.

The ventilation-perfusion ratio decreases down the lung.

Front 95

Does high V/Q ratio affect O2 or CO2 transfer more? What about shunts?

Back 95

High V/Q affects CO2 transfer more because alveoli can't help remove CO2 from blood if they are not being perfused. Shunts affect O2 transfer more.

Front 96

Five causes of hypoxemia (low O2 in blood)

Back 96

1. Inadequate pO2 in inspired air (high altitude)
2. hypoventilation
3. diffusion abnormalities (pulmonary edema)
4. V/Q nonuniformity
5. shunt

Front 97

What is the conducting portion of the respiratory system?

Back 97

nasal cavities, pharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles

warm, humidify air

Front 98

What is the respiratory portion of the respiratory system?

Back 98

respiratory bronchioles, alveoli ducts, alveolar sacs, alveoli

exchange gas

Front 99

which cartilage is most important in the larynx (open and close glottis)

Back 99

arytenoids

Front 100

What is the only muscle that opens the vocal cords (sole abductor)

Back 100

posterior cricoarytenoid

Front 101

Principle adductor of vocal cords

Back 101

lateral cricoarytenoid

Front 102

what is the main innervation of the larynx? Which side has the nerve deep in the chest?

Back 102

recurrent laryngeal nerves - left goes around aorta deep in chest (injury in chest can cause vocal cord paralysis)

Exception: cricothyroid innervated by superior laryngeal nerve

Front 103

what is the only cartilage that goes all the way around the larynx?

Back 103

cricoid cartilage

Front 104

what is the histology of the epiglottis?

Back 104

first 2/3 - non keratinized stratified squamous

last 1/3 - pseudostratified columnar ciliated

Front 105

true vocal cords epithelium?

false vocal cord epithelium?

Back 105

true: nonkeratinized stratified squamous

false: PSCC (also has glands so some mucus produced here during cold)

Front 106

Which bronchus is more steep?

Back 106

Left - distance greater than right before branching into segmental bronchi

Front 107

What is the angle of Lewk?

Back 107

carina splits here

Front 108

which vessels have same diameter as bronchi?

Back 108

pulmonary arteries

Front 109

What is the relation of the right/left pulmonary arteries and the bronchi?

Back 109

Right PA goes OVER bronchus; left goes under

pulmonary veins run in between segments of the lung

Front 110

Segments of R and L lobe

Back 110

R = 3,2,5
L = 4 (2 of lingula),4

Front 111

Bronchus vs trachea

Back 111

bronchus: irregular lumen, alveoli surrounding airway, cartilage plates

trachea: smooth lumen, muscle all the way around, Goblet cells, C shaped rings of cartilage

bronchioles - irregular lumen, but NO cartilage plates, CLara cells

Front 112

Histology of terminal bronchiole

Back 112

simple cuboidal cilliated, clara cells, macrophages, no cartilage

Front 113

Type I vs Type II alveolar cells

Back 113

Type I: epithelial cells that cover alveolus (Blood air barrier)

Type II: produce surfactant, help keep alveolus open

Front 114

what allows for collateral ventilation in the lungs?

Back 114

Pores of Kohn

Front 115

does the alveoli have mucus producing cells?

Back 115

no

Front 116

Where do bigger particles generally deposit in the airway? What about smaller particles?

Back 116

bigger particles (larger than 5 microns) in nasopharynx; smaller in bronchi, airways, alveoli

Front 117

Function of periciliary layer

Back 117

allows cilia to beat

Front 118

What is 9+2 cilia?

Back 118

9 outer doublets, one central pair of microtubules; each has dynein arms to help them move

Front 119

What is 9+0 cilia?

Back 119

no central pair of microtubules; can only sense or move in circles

Front 120

What is the role of Ca and cAMP in cilia?

Back 120

increase these two and you see increased ciliary beating

Front 121

What are the three things in Primary ciliary dykinesia (formerly Karagener syndrome)

Back 121

situs inversus, sinusitis, bronchiectasis (dilation)

all related to malfunction of cilia in development

Front 122

What is the mutation in cystic fibrosis?

Back 122

CFTR gene, problem with chloride channels so water cannot go out into periciliary layer

Front 123

If you breath in dry, cold air, what happens to mucociliary clearance?

Back 123

it stops - need ventilators with warm and humidified air

Front 124

Treatment of mucociliary dysfunction?

Back 124

B-agonists and methylxanthines, recombinant DNase, amiloride (increases intracellular Ca)

Front 125

What's alveolar proteinosis?

Back 125

Antibodies that are against GM-CSF, so alveolar macs can't clear alveolar space

Front 126

Silicosis

Back 126

eggshell calcification on hilum, dust, occupational problems

Front 127

Which lymph nodes are located at the carina?

Back 127

tracheobronchial lymph nodes

Front 128

What is a lobule supplied by?

Back 128

bronchiole

Front 129

Which muscle is not innervated by right recurrent laryngeal nerve?

Back 129

cricothyroid

Front 130

The inferior border of a lung projects into the ______ pleural recess.

Back 130

Costodiaphragmatic

Front 131

the only muscle that abducts the vocal ligament is

Back 131

posterior cricoarytenoid

Front 132

What are the components of the blood air barrier?

Back 132

fused basal lamina, type 1 alveolar cell

Front 133

Which volumes are increased in obstructive lung disease?

Back 133

RV, FRC, TLC

Front 134

total compliance =

Back 134

air-alveolar